1. Field of the Invention
The present invention relates to determining a parameter of a test material and, more particularly, to passing a pair of measuring signals along a pair of different length signal paths within the test material to obtain a pair of measurements from which at least one parameter of the test material is determined.
2. Description of Related Art
The measurement of test materials and particularly those test materials in a liquid or fluid state has been accomplished by a number of mechanisms.
For example, U.S. Pat. No. 3,939,707 discloses a cross-sectional visualization of the portion of the vessel to be examined, the portion lying in a plane of the visualization.
U.S. Pat. No. 4,257,278 discloses a quantitative volume blood flow measurement by an ultrasound imaging system having a Doppler modality.
U.S. Pat. No. 5,095,514 discloses a fiber optic sensor having a body of a matrix material that includes an embedded length of optical fiber, the body being arranged such that when exposed to an external disturbance, a transduction effect will cause corresponding mechanical stresses and strains to be developed internally and applied to the fiber. The resulting stresses and strains in the fiber cause a modification of the light transmission behavior that can be detected in the passage of light through the fiber optic length.
U.S. Pat. No. 6,216,544 discloses an ultrasonic flowmeter for measuring a flow of a fluid by use of an ultrasonic wave. The flowmeter includes a flow measurement section and a pair of ultrasonic oscillators constructed so that the influence of the phase difference between the direct wave and the reflected wave on the measurement results is reduced.
U.S. Pat. No. 6,318,179 discloses an ultrasound system for imaging a subject, having a first matter and a second matter, with the first matter moving with respect to the second matter in a first direction. In such an environment, the preferred embodiment enables determination of the quantitative movement of the first matter with respect to the second matter by transmitting into the subject a beam of ultrasound waves having a predetermined size and defining a plurality of beam positions and a beam axis moved in one or more scan directions having one or more scan direction components parallel to the first direction. First reflected ultrasound waves are received from the first matter and second ultrasound waves are received from the second matter in response to the beam positions in the one or more scan directions.
However, the need remains for increasing the accuracy of the determined parameters of the test material. The need further exists for reducing or eliminating the influence of a probe, a container or conduit parameters as well as transient variables such as temperature or pressure. The need also exists for a system that can provide simultaneous measurement of several parameters of the test material, wherein the measured results form components of a matrix to allow additional increase in accuracy and reliability through data processing.